Hot gas machine



E. FEZER ET AL May 5, 1970 HOT GAS MACHINE 3 Sheets-Sheet 1 Filed Aug. 23, 1968 United States Patent 3,509,718 HOT GAS MACHINE Eberhard Fezer, Essen-Bredeney, and Wilhelm Hoheuhinnebusch, Essen, Germany, assiguors to Fried. Krupp Gesellschaft mit beschrankter Haftung, Essen, Germany Filed Aug. 23, 1968, Ser. No. 754,923 Claims priority, application Germany, Aug. 25, 1967, 1,576,895 Int. Cl. F03g 7/06; F25b 9/00; F01k 23/02 US. CI. 60-24 7 Claims ABSTRACT OF THE DISCLOSURE A hot gas machine for converting heat energy into mechanical energy, which comprises first and second housing chambers variable in volume and respectively formed by first and second epitrochoidal housing means and by first and second triangular pistons having their interior subdivided into piston chambers, said pistons being rotatable in said housing means on an eccentric shaft while being interconnected by double wall pipe means, the housing chambers pertaining to said first piston forming hot chambers and the housing chambers pertaining to said second piston forming cold chambers, each hot chamber communicating with a cold chamber through passage means in said pistons which establish communication between said housing chambers and the respective piston chambers pertaining thereto, said double wall pipe having an annular intermediate section with regenerator means therein.

The present invention relates to a hot gas machine for converting heat energy into mechanical energy, according to which two chambers variable in volume and arranged in phase displacement are in open communication with each other and receive a quantity of working gas which in toto remains the same. The contents of the one chamber representing the hot chamber is kept at a higher temperature by means of a heat exchanger forming a heater, whereas the contents of the other chamber representing the cold chamber is kept at a lower temperature by means of a heat exchanger forming a cooler, a generator being arranged in the open connection between the hot and the cold chambers.

Machines of this type are known as piston stroke machines with crank drive or swash plate drive. These machines have the drawback that in view of the necessary lead of movement of the hot piston arrangement with regard to the cold piston arrangement, an even larger and more expensive balancing device is required than the already large and expensive balancing device necessary for piston stroke machines.

It is, therefore, an object of the present invention to provide a hot gas machine which will overcome the above mentioned drawbacks.

It is another object of this invention to provide a hot gas machine in which rotary elements are employed.

These and other objects and advantages of the invention will appear more clearly from the following specification in connection with the accompanying drawings, in which:

FIG. 1 is a diagrammatic longitudinal section through a hot gas machine with the housings and pistons of the two circular piston arrangements arranged congruently with regard to each other.

FIG. 2 respectively illustrates in cross-section the two pistons arranged one after another in FIG. 1.

FIGS. 3-10 respectively illustrate different positions of the two pistons during a rotary movement of the pistons in a hot gas machine, the housing and pistons being turned with regard to each other.

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A hot gas machine according to the present invention is characterized primarily in that the volume variable chambers are formed by the individual chambers of two circular piston arrangements with two arched epitrochoidal housings with a triangular piston each, the pistons of said circular piston arrangements being interconnected through a ring pipe so as not to rotate relative to each other while being rotatable on a common eccentric shaft. The three chambers of one arrangement are hot chambers and the three chambers of the other arrangement are cold chambers. Each hot chamber is in communication with a cold chamber through one piston bottom opening, through a piston bottom partial chamber in the interior of the piston, and through an annular pipe sector chamber between the two pistons which contains the generator. Such an arrangement brings about a relatively simple realization of the principle of the hot gas machine. The machine has a high mechanical degree of efiiciency which exceeds that of a circular piston machine with internal combustion; because the employed circular piston arrangements are either hot or cold, an essential temperature change within the individual circular piston arrangements does not take place, and thus a distortion of structural elements which produces mechanical friction losses will be impossible.

According to a further development of the invention it is suggested that the partial piston chambers are formed by partitions which extend from the center of the piston bottoms approximately normally inwardly, and it is furthermore suggested that the piston bottom openings in the hot chambers are arranged in those piston bottom portions which are considered the front portions when looking in the direction of rotation of the piston. The bottom openings in the cold chambers are located in those piston portions which are the rear portions when looking in the direction of rotation of the piston. In this way the required phase displacement between the volumetric changes in the hot and cold arrangement can be realized to the major extent in a most simple manner. Inasmuch as the respective oppositely located piston inner chambers are communicating with each other through the respective ring pipe sector chamber while each piston inner chamber of the cold arrangement leads into a chamber which is the next one with regard to the chamber into which the associated piston inner chamber of the hot arrangement leads, the lead of the volumetric change in the hot arrangement will in view of the provided steps be represented by an eccentric angle of For obtaining the most favorable phase displacement between the hot and the cold arrangement, it is furthermore suggested to rotatably offset the housings of the two circular piston arrangements and consequently the two pistons relative to the eccentric shaft axis or eccentric axis. In this connection it is to be noted that in conformity with the transmission ratio between eccentric shaft and piston, the turning angles of piston and housing have to be dimensioned differently. This ofisetting can be realized very economically without additional structural costs. Advantageousy, the ring pipe which interconnects the respective oppositely located chambers is over a portion of its length broadened in a dis-shaped manner for receiving the generators. Thus, also the generators are forming part of the masses which take part in the rotary movement for which it is very simple to obtain a mass compensation in view of their symmetric position with regard to the eccentric shaft.

In order to obtain a most favorable heat supply to and heat withdrawal from the working gas, it is suggested according to the present invention to provide a heat exchanger in each piston chamber, said heat exchanger extending through said last mentioned chambers and leading to the end faces of the piston. With such a construction, the surfaces of the heat exchanger are blade-shaped in such a way that a How of the heating and cooling gas through the outer surfaces of the blades is favorably influenced, and the working gas passes through the inner chamber of the blades.

Furthermore, it is suggested to subject the heat exchangers not directly to the heating and cooling gas, but to the same quantities of an intermediate medium and in the hot and in the cold arrangement. This intermediate medium will in its turn be in heat exchange with the heating and cooling medium.

Referring now to the drawings in detail, the hot gas machine according to FIGS. 1 and 2 comprises two housings 1 and 2 with epitrochoidal inner contour and two triangular pistons 3 and 4 rotating therein in clockwise direction. The two pistons 3 and 4 are firmly interconnected by means of a ring pipe subdivided into three ring pipe chambers 5, said pistons 3 and 4 being mounted on an eccentric shaft 6. The inner volume of the pistons 3 and 4 is subdivided by partitions 7 into three piston chambers 8 and 9 respectively. In each piston chamber 8 and 9 there is respectively arranged a heat exchanger which in the hot arrangement 1, 3 is formed by a heater 10 and in the cold arrangement 2, 4 is formed by a cooler 11. The piston chambers 8 and 9 communicate through openings 12 and 13 in the piston bottom with the chambers 14 and 15 on one hand and through the ring pipe sectional chambers 5 are in pairs in open communication with each other. The chambers 5 are in the middle between pistons 3 and 4 widened and contain regenerators 16 which during the fiow of hot working gases therethrough absorb heat, store the same and during the subsequent fiow of the now cold working gas in reverse direction convey the stored heat again to the working gas. The heat exchangers 10, 11 passed through by the working gas are acted upon by an intermediate medium which in the hot as well as in the cold arrangement flows around the inner housing chamber in a respective closed circuit 17, 18. The flow of the intermediate medium is produced by the movement of the pistons 3 and 4 in combination with a blade-shaped design of the surfaces of the heat exchangers 10 and 11. The intermediate medium of the hot arrangement is heated up by the heated up hot gas which passes through the conduits 19 and through burners 20. Prior to entering the burners 20, the combustion air is passed through preheating conduits 21. In the cold arrangement, the intermediate medium is cooled by the cooling gas which delivered by a blower 22 passes through cooling gas guiding means 23 which similar to the hot gas guiding means 19 are so designed that they will assure a best possible heat transfer.

In contrast to the arrangements shown in FIGS. 1 and 2, with the embodiment of FIGS. 3-10 the housings 1, 2 and pistons 3, 4 are offset with regard to each other. The piston chambers 24 and 25 are associated with each other. The direction of rotation of the pistons 3, 4 is counterclockwise. In View of the phase displacement which occurs when housing and piston are located in a congruent manner but with the piston bottom openings in the hot arrangement located in front and with the piston bottom openings in the cold arrangement located in the rear, and in view of the offsetting of the housings 1 and 2 and the pistons 3 and 4, there is obtained a favorable lead of the volumetric changes in the hot arrangement relative to the cold arrangement at a 150 eccentric angle. A slight displacement of the foot points of the partitions 7 from the center of the piston bottom toward the rear was considered advisable.

According to the piston positions illustrated in FIG. 3, the total working gas quantity associated with the chambers 24 and 25 and with the corresponding piston chambers 26 and 27 and their connection has the greatest volume. Under the influence of the heat exchange, however, it has been found that the lowest pressure for the working gas quantity under consideration occurs only at the positions of FIG. 4. FIG. 5 shows the positions for the smallest volume. The highest pressure will again 1n view of the heat exchange occur only with the positions of FIG. 6. Thereupon (for the working gas quantity under consideration), an expansion will start. The largest volume will again be obtained when the piston positions are those of FIG. 7 which correspond to those of FIG. 3. The pertaining chambers are, however, in this instance located in the lower housing section. The further course of the changes in the volume according to FIGS. 8, 9 and 10 analogously corresponds to that of FIGS. 4, 5 and 6. During the compression between the time periods according to FIGS. 4 and 6 which occurs primarily in the cold arrangement, in the first portion of this time period working gas is displaced from the hot to the cold arrangement, and in the second portion of said time period working gas is displaced from the cold to the hot arrangement. During the expansion between the time periods of FIGS. 6 and 8 which occurs primarily in the hot arrangement, in the first portion of this time period working gas is displaced from the cold to the hot arrangement and in'the second portion working gas is displaced from the hot to the cold arrangement.

It is, of course, to be understood that the present invention is, by no means, limited to the particular showing in the drawings. The fundamental idea of the present invention can be employed also with other rotary piston machines, and the modification of the hot gas machine according to the invention into a gas refrigerating machine is possible, the scope of the invention being defined by the appended claims.

What we claim is:

1. A hot gas machine for converting heat energy into mechanical energy, which includes: first housing means with epitrochoidal inner contour, second housing means with epitrochoidal inner contour, first and second hollow rotary pistons with triangular outer contour respectively rotatable in said first and second housing means and defining therewith three housing chambers variable in volume in conformity with the rotary movement of said pistons, each of said pistons having its interior partitioned into three piston chambers and each of said piston chambers being provided with a peripheral opening establishing communication between the respective piston chamber and the respective adjacent housing chamber, eccentric shaft means rotatably supporting said first and second pistons, double wall pipe means defining annular passage means and fixedly interconnecting said first and second pistons for rotation in unison about said eccentric shaft means, said annular passage means being partitioned into three sectional passages respectively connecting the piston chambers of said first piston with the piston chambers of said second piston, a plurality of first heat exchanger means in the form of heater means respectively arranged in said first piston chambers to heat the same, second heat exchanger means respectively arranged in said second piston chambers in the form of cooling means for cooling the same and a plurality of regenerator means respectively arranged in said sectional passages intermediate said first and second pistons.

2. A hot gas machine according to claim 1, in which said piston chambers are formed partially by the outer piston walls and by partition walls extending from the central portion of said outer walls approximately vertically thereto to the respective adjacent portion of said double wall pipe means, and in which the peripheral openings establishing communication between the respective piston chamber pertaining to said first piston and the respective adjacent housing chamber are arranged in those outer piston walls of said first piston which in the direction of rotation of said first piston are located in front and in which the peripheral openings establishing communication between the respective piston chamber pertaining to said second piston and the respective adjacent second pistons are offset with regard to each other in 5 respect to the axis of the eccentric shaft means.

4. A hot gas machine according to claim 1, in which said double wall pipe means is between said first and second housing means provided with a radially outwardly extending hollow disc-shaped portion, and in which said regenerator means are located within said hollow disc means.

5. A hot gas machine according to claim 1, in which said heat exchanger means in said first and second piston chambers extend therethrough and lead to the end faces of the respective pistons.

6. A hot gas machine according to claim 5, in which the surfaces of the heat exchanger means are provided with blades which are designed so that the flow of the 20 heating and cooling gases is aided by the outer surfaces of said blades and that Working gas passing through said 6 heat exchanger means moves through the inner space of said blades.

7. A hot gas machine according to claim 1, which includes means for passing an intermediate medium of constant quantity to said heat exchangers for actuating the same, said intermediate medium being in heat exchange with said heating means and cooling means.

References Cited UNITED STATES PATENTS 2/ 1968 Kelly 60 -24 2/ 1969 Rubin 6024 FOREIGN PATENTS 962,996 12/1949 France.

US. Cl. X.R. 62-6 

